The utility of computer systems can be enhanced by providing better user interfaces. User interfaces for computers systems have evolved significantly since the personal computer (PC) first became widely available. Early PCs used rather primitive user input devices, such as the serial mouse, and only provided a monochrome display. However, the vast improvement in microprocessors, available memory, and programming functionality have all contributed to the advancement of user interface design and the development of user friendly graphic operating systems and hardware.
One particular area of advancement in user interface technology pertains to an interactive display system. Such systems usually include an enclosure, a display surface, various image projection and user input detection equipment, and a computer. An interactive display system can include or be coupled to a general purpose computing device. A significant advantage of the interactive display system is that it enables user interaction directly with a display surface. A user can provide input to this type of system by directly touching the interactive display surface with one or more fingers, or by making a gesture just above the interactive display surface. However, interactive display systems can suffer certain limitations and disadvantages if constrained to implement a graphical user interface (GUI) like that employed by applications designed to be executed on conventional personal computers (PCs). For example, a user of an interactive display system can interact with a horizontal display surface from any side. By its nature, a horizontal interactive display surface is not like a conventional vertical display that has a “top” and “bottom” and is intended to be viewed by a person sitting in front of the conventional display. In contrast to a conventional vertically oriented display, users who are disposed on opposite sides of an interactive display will clearly prefer a graphical user interface that is oriented relative to the user, in order to have a similar user experience. Thus, the graphical user interface that is oriented appropriate for the user on one side of the horizontal interactive display surface will appear inverted to the user on the other side of the interactive display surface, and vice versa. Therefore there is presently motivation for developing solutions to these and other limitations of the prior art that interfere with the user's enjoyment of a generally horizontal interactive display surface. It would be clearly be preferable to provide a dynamic orientation free user interface, for use with applications executed on interactive display systems.